Panel illumination



v- 4, 19 M. J. CASERIO ETAL 2,858,632

PANEL ILLUMINATION Filed June 27,

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PANEL ILLUMINATION Martin J. Caserio and Henry C. Stuerzl, Flint, Mich., assignors to'General Motors Corporation, Detroit, Mich a corporation of Delaware Application June 27, 1955, Serial No. 518,018

5 Claims. (Chm-132) This invention relates to illuminating means and more particularly to means for illuminating. avtransparent or luminescent panel. In many instances, such for example as in advertising signs or instrument panels, fiat panels bearing indicia, lettering, or scales must be furnished with illumination. Various means have been used in the past to provide illumination for such configurations or indicia which include fluorescent means irradiated or activated by an external source of light, so-called edge lighting, or other indirect lighting schemes.

More recently a different type of lighting has been introduced which may be defined as an electro-luminescent lamp. These lamps consist ofv laminated sheets of material which when energized produce a glow over the whole surface to illuminate the surroundings. Such a lighting means is disclosed in United States Patent to Eric L. Mager 2,566,349, issued September 4, 1951. In this form a glass or other transparent plate is providedupon one face of which is secured a thin sheet of tin chloride which is electrically conductive and transparent. Next in laminated assembly is a sheet offluorescent phosphor which is electrically insulating and which is lastly covered witha sheet of aluminum also acting as an electrical'conductor. As stated in the above mentioned Mager patent in column 1 beginning at line 9: In the electroluminescent lamp the light appears to be produced only when the voltage is applied and when it is removed, or when the voltage is changed. Such lamps are accordingly most effective when used on alternating, pulsating or otherwise varying currentsff Thus, where an alternating electric voltage of the proper cycle and of the proper value is applied to the sheets of tin chloride and aluminum, acontinuously variable electrical field is setup between the two which causes the intermediate fluorescent phosphor sheet to glow. Since the tin chloride sheet is transparent, the glow is visible through the glass and the whole panel appears to be illuminated. Such type of illumination is, however, plain and even over the surface. This does not provide for the illumination of any scales or indicia such as would be necessary in instrument panels or in advertising signs 0 various types. r

It is therefore an object in makingithis invention-to provide panel illumination incorporating desired configurations such as indicia for use in instrumentation'or advertising. V

It is a further object in making this invention to provide laminar construction incorporating both configuration and illuminating features therein.

It is a still further object in making this invention to provide illuminating means having built-in configurations.

With these and other objects in view which will become apparent as the specification proceeds, our invention will be best understood by reference to the following specification and claims and the illustrations in the accompanying drawings, in which:

. Figure 1 is a plan view of one element of an instrument panel cluster incorporating the features of our invention.

' United States Patent;

.Figure 2 is an enlarged sectional view taken on the line 2-2 of Figure 1.

Figure 3 is an exploded view of the components of our laminated structure to show their relative positions; and Figure 4 is a cross section showing the elements in spaced relation of a modified form of our invention.

Referring now moreparticularly to Figures 1 and 2, there is shown therein, as an example only, a speedometer dial 2 which is used with automotive vehicles. The dial plate issupported in a framework 4 and an indicating pointer 6 is adapted to move across the dial to indicate the vehicle speed. The dial itself is best shown in the section Figure 2. It consists of several plates of differing materials laminated together and the assembly is mounted in a supporting bracket 8. This assembly consists, and reference is herein made to Figure 3 as clearly showing the components, of a front plate 10 which is transparent and may, forexample, be formed of glass or plastic. The next sheet 12 is formed of tin chloride which has two characteristics which are useful: one, it is electrically conductive, and two, it is substantially transparent. This sheet necessarily is relatively thin.

In order to obtain some means to provide intelligence, the next layer consists of figures or configurations of the desired forms. In this example these would take the shape of numerals 14 which are placed on the surface of If paint is used it may be colored to give the desired.

aesthetic elfect to the panel. Lastly, a sheet 18 of aluminum or other similar material is applied, which is, of course, electrically conductive, and which will be insulated from sheet 12 by both the fluorescent phosphor and insulating sheet 16. These members are laminated together by any desired means which holds them in juxtaposition. When they are in position, alternating current electrical power is applied to the tin chloride sheet 12 and the aluminum sheet 18 through power lines 20 and 22. The application of power to these two surfaces creates an electrical field between the two, which field causes the fluorescent phosphor layer to glow. In this instance this layer consists of numerals and these numerals glow. They are visible through the front of the assembly and appear to be unsupported in space. Therefore, when such laminar assembly is supported in the bracket 8 and electric power applied, it produces a very satisfactory night illumination for such adevice as a speedometer of an automobile.

In some instances it may be desirable to not only illuminate the configurations supported in a laminar panel,

asabove described, but also to illuminate other devices in the area. Again using as an example the speedometer panel of an automotive vehicle, it might be desirable to illuminate the cavity behind the instrument panel to pro vide illumination for the cigarette lighter so that it may be easily found. Figure 4 therefore shows a modified form of our invention which includes not only configuration illumination but alsoan area of the panel for projecting rays in the opposite direction for any desired use. Referring more particularly to Figure 4, the same reference numerals will be applied to similar members and the assembly consists of a front plate 10 which may be of glass, a second layer 12 of tin chloride, which is thin and transparent and electrically conductive. An indicia or vides a certain amountof illumination radiating from the front face as indicated by'the arrows.

'If itis'desired to also havesome*illuininationradiating to the rear'to illuminate other parts,- such as gagesd-sp'eedometer pointers, etc., thisi'sprovid'ed by duplicating'sim ilar stru'cture'on the rear faceof aluminum sheet 18, utilizing that sheet as a common sheet of both-sections of lumination. While it would be perfectly 'plausible'to make the size sheet on the rear face of exactly'ihe sarne size asthe front, it can also be made any partial size-as desired and in this example isonly of a relatively small'sizer The first part to be laminated to the lower rear'surface of the sheet 18 is a sheet of fluorescent phosphor 24. This sheet24 in this instance is shown as a complete layer since his only desired to obtain radiated illumination in thisdirection and not any particularlaminated configuration or indicia illumination. The fluorescent phosphor layer 24 is therefore of the same size-as the next in order tin chloride sheet 26 and acts 'as an electrical insulator between that sheet and sheet 18. 'La'stly in order is a transparentor glass sheet'28 which 'completes the smallerlaminar assembly on the back face of aluminum'conductor sheet 18.

-When electrical power-is applied across power lines 20 and 22 in Figure 4, theconfigurations in the sheet 14 are illuminated. By then connecting input line 20 through tie line 30 with the tin chloride sheet 26, a similar field is set up in the rear laminar ection between plates 26 and aluminum conductor 18 In this instance, however, the fluorescent phosphor sheet 24 will glow evenly over the whole area producing rays of illumination to the rear to be used for any desired purpose. "Figure 4;therefore, shows a combination system for illuminating indicia or desired configurations and at the same time providing external illumination in another direction for ;any desired associated pieces of equipment. 'If'jit is desired to 'view a pointer such'as 6 through the panel instead of having the pointer move in front of the panel, a clear section or window may be provided by omitting an'area of insulating material 16 and a-like area of the conductive sheet 18.

This will provide'a' 't'ransparent area in the panel and parts i on the opposite-side of the 'panel'may'be viewed there-' through without aifectingthe operation of the rest of the panel.

We clai'rn'f H v p r Y 1. In illu inating meansial thin transparent electrically conductive sheet, electroluminescent phosphor means having a desired configuration secured to one side of said conductive sheet, an electricallyinsulatinglayer secured to that side'of the sheet and covering the configurations and a second sheet of electrically conductive material se-' cured adjacent the electrically insulating layer to produce a variable the conductive sheets when voltage is applied thereacross to cause the electro-luminescent phosphor means to glow to produce indicating material.

2. In illuminating means,-a laminar assembly formed of a sheet of aluminum, a layer of electrical insulating colored material, a:sect'ion:'-of-electro-luminescent material cut to a desiredvconfiguration to provide intelligence, a sheet of-tinichlorideiwhich is transparent and a layer of transparent material so that upon application of alternating current electrical power to the aluminum and tin chloride sheets-'a-variable'fi'eld will be set up between them to cause the electro-luminescentmaterial to radiate which is visible through thetin chloride sheet and transparent panel with a colored background.

3. In illuminating means, a first member of electrically conductive materiak-a plurality ofsecond members of electrically. conductive mate'rial mounted in insulated relation on each sideofsaid' first member, electro-luminescent meansinterposed betweenthe first and each second inern:

ber'to radiatewhen a potential is applied to the first and second members, atleast one of the electro-luminescent means being formed in a configuration to convey intelligence and the otherto providegeneral illumination,

'41- 'In illuminating means, a first member of electrically conductive material, a plurality of second members of electrically conductive material mounted ininsulatedrelation o'neach' side of said first member, electro-luminescent 'm'eansinterposed between the first and each secondmemberto radiate when a-potentialis appliedto the first andse'condme'r'nbers, at least one of the electro-luminescent means beingformedin a configuration to convey in-- telligence, and said second members being sufficiently thin tobe transparent tothe passage of light rays.

5 In illuminating means, a member of electricallyconductive material, a layer of insulating material supported over one face of the member, electro-lurninescent 'means cut in a desired configuration and aflixed to said insulating layer, a sheet of transparent, electrically conductive material mounted over the electro-luminescent means and means to applya potential to the member of electrically conductive material and the transparent sheet of electrically conductive material to develop avariable field between the two to cause the electro-luminescent means to glow, a sheet of electro-luminescentmaterial secured to the opposite face of the first-named member of electrically conductive material, a second sheet of transparent electrically conductive materialsecured to the sheet of electroluminescent material and electrically connected to the first transparent sheet to "providea variable electric field on the opposite-side or the first-named member also to provide general illumination. 7

References Cited in the file of this patent V UNITED STATES PATENTS ,Kohlhauer etal. Aug. 30, 1949 2,566,349 Mager Sept. 4, 1951 2,716,298 i Spielmannet al. Aug. 30, 1955 2,721,808 Roberts et a1. Oct. 25, 1955 

1. IN ILLUMINATING MEANS, A THIN TANSPARENT ELECTRICALLY CONDUCTIVE SHEET, ELECTRO-LUMINESCENT PHOSPHOR MEANS HAVING A DESIRED CONFIGURATION SECURED TO ONE SIDE OF SAID CONDUCTIVE SHEET, AN ELECTRICALLY INSULATING LAYER SECURED THAT SIDE OF THE SHEET AND COVERING THE CONFIGURATIONS AND A SECOND SHEET OF ELECTRICALLY CONDUCTIVE MATERIAL SECURED ADJACENT THE ELECTRICALLY INSULATING LAYER TO PRODUCE A VARIABLE FIELD BETWEEN THE TWO CONDUCTIVE SHEETS WHEN VOLTAGE IS APPLIED THEREACROSS TO CAUSE THE ELECTRO-LUMINESCENT PHOSPHOR MEANS TO GLOW TO PRODUCE INDICATING MATERIAL. 